Microanalysis of indoor aerosols and the impact of a Compact High-Efficiency Particulate air (HEPA) filter system

Aerosol particles in municipal atmospheres are of increasing public health concern; however, since most of our time is spent indoors, indoor aerosols must be researched in counterpart. Compact High-Efficiency Particulate Air (HEPA) filter systems are commonly employed in residences to alleviate airb orne dust concentrations. In this study, a detailed and original methodolog y was used to determine concentrations and types of submicrometer aerosols, as well as of large (>4 mu m) dust particles. Scanning electron microscopy was used to quantify and characterize ambient aerosols collected from filt ered and non-filtered rooms. Particle concentrations were significantly low er in samples collected in the presence of the filter system (mean 23 to 8 coarse particles liter(-1), 63% reduction; 13 to 3 inorganic submicron part icles cm(-3), 76% reduction; 85 to 33 total submicron particles cm(-3) 62% reduction; all P<0.05). This study provides a new methodology for analysis of indoor aerosols and new data on their physico-chemical characteristics. Since the filter systems are effective at reducing submicron aerosol concen trations, they may improve the health of individuals such as asthmatics, wh o experience health problems caused by anthropogenic fine particles.